This project will investigate the introduction and impact of mandatory licensure of registered nurses. The objective of this project is to provide a better basis for evaluating the consequences of mandatory licensure and reasons why it has spread in nursing and other occupations in the health sector. The project hypothesizes that mandatory licensure has been introduced for registered nurses in response to changes in employment patterns in hospitals and increased use of practical nurses. The project hypothesizes that the impact of mandatory licensure has been to increase both the wages and total employment of registered nurses in areas with this type of regulation, potentially increasing the cost of health services. These hypotheses will be tested using cross-section and time-series data for states and multiple regression analysis, supplemented by case studies of the introduction of mandatory licensure in selected states.